1. Field of the Invention
The invention relates to a fuel injection arrangement for the cylinder of an internal combustion engine, with a fuel injector mounted on the cylinder head of the cylinder.
2. Background Art
A fuel injection arrangement of the type initially mentioned is known from U.S. Pat. No. 6,009,856. In this arrangement, the fuel injector serves, in a known way, for injecting fuel into the cylinder space of the internal combustion engine. In modern very high-performance fuel injection systems, pronounced vibrations and noise emissions occur during operation. In order to reduce these emissions, it is proposed, according to U.S. Pat. No. 6,009,856, to embed the fuel injector into a cylindrical sleeve by means of an elastic noise-damping substance. This sleeve is supported with its lower end face on the cylinder head, while the fuel injector is screwed to the cylinder head via flanges and screws running in the longitudinal direction of the fuel injector. Depending on the amount by which the screws are tightened, the fuel injector can be pressed to a varying depth into the embedding substance in the sleeve. In particular, in the mounted state, the screw connections of the fuel injector are tightened so firmly that the associated flanges sit on the upper end face of the sleeve. However, fastening the fuel injector in this way is highly complicated, since it requires the complete embedding of the fuel injector into an elastic substance and the surrounding of the latter by a sleeve. Renewal of the bedding in the event of the latter being damaged or undergoing aging is not possible, in practice, in the arrangement already known.
Against this background, the object of the present invention was to provide a simplified fuel injection arrangement with good noise insulation.
The fuel injection arrangement in accordance with the present invention includes a fuel injector that is fastened to a cylinder head of an internal combustion engine. The arrangement is defined in that a damping material is arranged between the contact faces, extending, as a rule, transversely, but also up to an angle of 45xc2x0, to the longitudinal axis of the fuel injector, of the fuel injector, on the one hand, and of the cylinder head, on the other hand.
When the fuel injector is fastened by means of holding forces running in the axial direction, for example by means of screws running in the axial direction, the contact faces, extending transversely to the longitudinal axis of the fuel injector, on the fuel injector, on the one hand, and on the cylinder head, on the other hand, are under a force load running essentially perpendicularly to the contact faces. This perpendicular force load is absorbed or transferred by the damping material between the contact faces, the damping material advantageously undergoing straightforward compression without shear forces.
In a further advantageous embodiment of the invention, the parting plane between the fuel injector and the cylinder head runs at an angle of 45xc2x0 to the longitudinal axis of the fuel injector.
The damping material is preferably designed in the form of a shim, surrounding the fuel injector annularly. Such an annular design of the damping material makes it possible to mount the damping material on the fuel injector in a particularly simple and at the same time reliable way.
According to a preferred embodiment of the invention, the damping material consists of a plurality of plies. In particular, it may consist of four to six plies. The plies can be constructed of different or same materials. By different plies of the damping material being used, the thickness of the entire layer can be set as required. Furthermore, by the use of different materials, each having special properties, a specific desired damping behavior can be set in a controlled way.
The layer-like damping material preferably has a total thickness of about 2 to 3 mm. In the case of a multiple damping materials, the layer-like damping material preferably includes various plies of the same thickness, for example five plies, each with a thickness of 0.5 mm.
The damping material may be metal, rubber and/or a plastic, in particular a tetrafluoroethylene material (Teflon(copyright)).
The materials used, on the one hand, must have the desired damping behavior for vibrations and noises which are generated in the fuel injector and, on the other hand, must have sufficient mechanical and thermal stability to withstand the loads to which they are exposed while the fuel injection arrangement is in operation. The materials mentioned above have proved particularly advantageous in this respect.
Further advantages, objects and features of the invention will become apparent from the following detailed description of the invention taken in conjunction with the accompanying figures showing illustrative embodiments of the invention.